The mission of the NIEHS Microarray Group (NMG) is to develop and advance an intramural research program that utilizes the advances in genomics and bioinformatics to address critical threats to human health as a consequence of environmental exposures. Specifically, the NMG is incorporating genome-wide gene expression analysis using microarray technology as well as emerging gene expression analysis technologies and developing bioinformatics approaches to address the NIEHS mission of reducing or eliminating these threats. Thus the goals of the NMG include: 1) the pursuit of mechanistic investigations of the impact of exposures on gene expression and alterations in critical cellular regulatory pathways, 2) the utilization of global gene expression changes following environmental stresses and bioinformatics tools to identify specific changes that are tightly linked with a deleterious human health outcome as patterns or biomarkers of a particular disease or toxic outcome, and 3) the continual development and implementation of new and better analytical and computational approaches to investigate genome-wide changes in gene expression. One consequence of this research program will be the accumulation of global gene expression information that will contribute to the population of public environmental health and toxicogenomics gene expression databases. Another is the development of computational algorithms which are well-suit to specifically mine across both global gene expression data and traditional toxicological measurements across multiple studies in order to elucidate biological pathways in model systems that are altered by toxic exposures or as a consequence in environmentally-induced diseases.